Organopolysiloxane compositions which cure at ambient temperature

ABSTRACT

iv. 0 to 100 parts of an optionally organosilicontreated inorganic filler; V. 0 TO 100 PARTS OF PLASTICISER AND/OR ORGANOSILICON STABILISER; AND VI. 0.5 TO 8 PARTS OF AN ORGANOSILICON RESIN CONSISTING OF UNITS OF THE FORMULAE R&#39;&#39;&#39;&#39;&#39;&#39;(CH3)2SiO0.5 and SiO2; Such compositions are particularly suitable for coating electric and electronic devices because neither they nor the elastomers obtained therefrom on curing corrode copper or other metals.   OR D. A TITANIUM CHELATE OF THE FORMULA (D):   An organopolysiloxane composition is provided which consists essentially of a mixture of the following ingredients by weight: I. 100 PARTS OF A Alpha , omega -DIHYDROXYDIORGANOPOLYSILOXANE POLYMER, OF VISCOSITY AT LEAST ABOUT 600 CPo at 25*C; ii. 1 to 15 parts of an organosilicon compound which is either A. A MONOMER OF THE FORMULA (A): RxSi((OCH2CH2)aOR&#39;&#39;)4 x, or B. A POLYMER RESULTING FROM THE PARTIAL HYDROLYSIS OF AT LEAST ONE MONOMER OF FORMULA Si(OR&#39;&#39;)4; iii. 0.2 to 6 parts of an organic derivative of titanium, which is either: A. A MONOMER OF THE FORMULA (B): Ti((OCH2CH2)bOR&#39;&#39;&#39;&#39;)4, b. a polymer resulting from the partial hydrolysis of at least one monomer of the formula Ti(OR&#39;&#39;&#39;&#39;)4; c. a titanium chelate of the formula (C):

United States Patent [191 Ceyzeriat et al.

[ 1 Nov. 25, 1975 ORGANOPOLYSILOXANE COMPOSITIONS WHICH CURE AT AMBIENTTEMPERATURE [75] Inventors: Louis Ceyzeriat, Lyon; Michel Letoffe,Ste-Foy-les-Lyon, both of France [73] Assignee: Rhone-Poulenc S.A.,Paris, France [22] Filed: Mar. 4, 1974 [21] Appl. No.: 447,501

[30] Foreign Application Priority Data Mar. 7, 1973 France 73.08143 [52]U.S. Cl. 260/37 SB; 260/29.l SB; 260/825 [51] Int. Cl. C08L 83/00 [58]Field of Search 260/37 SB, 825

[56] References Cited UNITED STATES PATENTS 3,527,659 9/1970 Keil260/825 X 3,689,454 9/1972 Smith et al. 260/37 88 X 3,779,986 12/1973Smith et al. 260/37 SB X Primary ExaminerLewis T. Jacobs Attorney,Agent, or FirmStevens, Davis, Miller & Mosher ABSTRACT Anorganopolysiloxane composition is provided which consists essentially ofa mixture of the following ingredients by weight:

i. 100 parts of a a,m-dihydroxydiorganopolysiloxane polymer, ofviscosity at least about 600 cPo at 25C;

ii. 1 to 15 parts of an organosilicon compound which is either a. amonomer of the formula (A):

b. a polymer resulting from the partial hydrolysis of at least onemonomer of formula Si(OR).,;

iii. 0.2 to 6 parts of an organic derivative of titanium, which iseither:

a. a monomer of the b. a polymer resulting from .the partial hydrolysisof at least one monomer of the formula ")4;

c. a titanium chelate of the formula (C):

formula (B):

o= /Q (R"O),,Ti C-R d. a titanium chelate of the formula (D):

CH o O= (RCH),./ Ti c R- \CH2 O \O C 0 optionally 8 Claims, No DrawingsORGANOPOLYSILOXANE COMPOSITIONS WHICH CURE AT AMBIENT TEMPERATURE Thepresent invention relates to organopolysiloxane compositions, which arestable when stored in the absence of moisture and which cure rapidly, atambient temperature or above, in the presence of water, for example themoisture in the atmosphere, to yield elastomers possessing good physicalproperties.

Organopolysiloxane composition which are stable when stored and whichcure when exposed to the atmosphere to yield elastomers, are alreadyknown; they are prepared by mixing suitable practically neutralingredients, mainly hydroxylic diorganopolysiloxane oils, alkoxysilanesand/or the products resulting from their partial hydrolysis, organicderivatives of titanium and inorganic fillers (see, for example, FrenchPat. Nos. 1,266,528 and 1,330,625).

However, no one such composition, which is employed in such fields asgluing, caulking, coating electrical parts and coating woven fabrics,possesses all the properties and qualities which would promote theirdevelopment on a large industrial scale. Thus, they rarelysimultaneously possess quick setting at the surface so as to preventdust from becoming embedded and avoid having to keep the coated partsimmobile for a long period, good stability when stored, and the abilityto yield elastomers having good mechanical properties.

The present invention provides new organopolysiloxane compositions whichpossess a combination of such qualities. These compositions are producedby mixing the following ingredients (the parts being by weight):

i. 100 parts of 01,1-dihydroxydiorganopolysiloxane polymers, ofviscosity at least 600 cPo at C, consisting essentially ofdiorganosiloxy units, the organic radicals bonded to the silicon atomsbeing alkyl radicals with one to three carbon atoms, halogenoalkylradicals with three or four carbon atoms, the vinyl radical, aryl orhalogenoaryl radicals with six to eight carbon atoms and cyanoalkylradicals with three or four carbon atoms, with the proviso that at least50% of these organic radicals are methyl radicals; ii. 1 to 15 parts oforganosilicon compounds chosen from either.

a. monomers of formula (A):R,Si[(OCH CH- ),,OR], in which R represents ahydrocarbon radical with one to eight carbon atoms, R represents analkyl radical with one to four carbon atoms, and and a independentlyrepresent zero or one, or

b. polymers resulting from the partial hydrolysis of these monomerswhich correspond to formula (A) in which a and .r are zero, that is tosay Si(O- )-l;

iii. 0.2 to 6 parts of organic derivatives of titanium,

chosen from:

a. monomers of formula (B): Ti[(OCH Cl-l ),,OR '1, in which R representsan alkyl radical with one to 10 carbon atoms and b represents zero, 1 or2, such that when 12 is zero, the alkyl radical has three to 10 carbonatoms and when b is 1 or 2, the alkyl radical has one to four carbonatoms,

b. polymers resulting from the partial hydrolysis of monomers of formula(B) in which b is zero, that is to say Ti(OR") and c. titanium chelatesof the formula (C):

in which Q represents an alkyl radical with one to four carbon atoms, aphenyl radical or an alkoxy radical with one to three carbon atoms; R"is as defined above in connection with formula (B) when b is zero; yrepresents 2 or 3; R represents a hydrogen atom, a methyl radical or achloromethyl radical; Q represents an alkyl radical with one to fivecarbon atoms or a chloromethyl radical; or R and Q together represent,together with the two carbon atoms to which they are attached, a phenylnucleus, in which case Q represents an alkoxy radical or a hydrogenatom; or

d. titanium chelates of formula (D):

in which R and R which may be identical or different, represent hydrogenatoms or methyl radicals, Q, Q and R are as defined above in connectionwith formula (C); n represents zero or 1;

iv. 0 to 100 parts of inorganic filler which may or may not have beentreated with organosilicon compounds; and

v. 0 to 100 parts of plasticisers and/or organosilicon stabilisers.These compositions are characterized in that, in order to prepare them,0.5 to 8 parts by weight of organosilicon resin consisting of units ofthe formulae R"'(CH SiO and SiO in which R represents an alkyl radicalwith one to three carbon atoms or the vinyl radical and the ratio of thenumber of R"'(CH SiO units to the number of SiO units is from 0.4/1 to1.2/1, are added.

The a,w-dihydroxydiorganopolysiloxane polymers used in the compositionsof the present invention have a viscosity of at least 600 cPo at 25C andpreferably 800 cPo at 25C; they are oily or gummy products depending ontheir degree of polymerisation and the nature of the radicals bonded tothe silicon atoms. They consist essentially of diorgansiloxy units butmonoorganosiloxy units may be present in an amount up to 2% by number.

Examples of the organic radicals bonded to the silicon atoms include:

alkyl radicals with one to three carbon atoms, namely methyl, ethyl andpropyl radicals,

halogenoalkyl radicals with three or four carbon atoms, such as3,3,3-trifluoro-propyl and 4,4,4-trifluoro-butyl radicals, aryl andhalogenoaryl radicals with six to eight carbon atoms, such as phenyl,tolyl, xylyl, chlorophenyl, dichlorophenyl, trichlorophenyl,tetrachlorophenyl and trifluoromethylphenyl radicals, and

cyanoalkyl radicals with three or four carbon atoms, such asbeta-cyanoethyl and gamma-cyanopropyl radicals.

Methyl radicals represent at least 50%, and preferably of the number oforganic radicals, In order to make it possible for the compositions toset more rapidly, it is generally advantageous to use polymers, theviscosity of which is at most a few million cPo at C, but neverthelessthe use of gums with viscosities as high as million cPo at 25C can beconsidered with very reactive organosilicon compounds and very reactiveorganic derivatives of titanium. Furthermore, mixtures of polymersprepared by combining polymers of very different molecular weights, andthus also of very different viscosities, are perfectly suitable.

The techniques for the preparation of these dihydroxylic polymers arenow well known; the technique mainly used consists of polymerisingdiorganocyclopolysiloxanes by means of a catalytic amount of an alkalineor acid agent and then treating the polymerisates with a calculatedamount of water, (see, for example, French Pat. Nos. 1,198,749 and1,134,005).

As already mentioned, 1 to 15 parts, and preferably 2 to 12 parts, ofmonomeric organosilicon compounds of formula (A): R,Si[(OCI-l CH ),,OR']or of polymeric organosilicon compounds resulting from the partialhydrolysis of these monomers of the formula Si(O- R),, are used per 100parts of a,m-dihydroxydiorganopolysiloxane polymers. Specific examplesof hydrocarbon radicals with one to eight carbon atoms, represented byR, include:

alkyl radicals with one to three carbon atoms namely methyl, ethyl andpropyl radicals; the vinyl radical; and aryl radicals with six to eightcarbon atoms such as phenyl, tolyl and xylyl radicals.

Specific examples of alkyl radicals with one to four carbon atoms,represented by R, include methyl, ethyl, propyl, isopropyl and butylradicals.

By way of indication, as monomers of formula (A), the following may beused, individually or as a mixture: methyltrimethoxysilane,methyltriethoxysilane, methyl-triisopropoxysilane,vinyltrimethoxysilane, vinyltriethoxysilane, phenyltrimethoxysilane,methyl-tris(methoxyethoxy)-silane, ethyl-tris-(methoxethoxy)-silane,vinyl-tris-(methoxyethoxy)-silane, propyl-tris-(methoxyethoxy)-silane,phenyl-tris-(methoxyethoxy)- silane, methyl silicate, ethyl silicate,propyl silicate, isopropyl silicate, butyl silicate,beta-(methoxy)-ethyl silicate and beta-(ethoxy)-ethyl silicate.

The polymers resulting from the partial hydrolysis of alkyl silicates offormula Si(OR") for example such silicates which have just beenmentioned, consist, for the most part, of units of the formula Si(OR) O,with a small proportion of units of the formulae (R'O) Si- O ROSiO andSiO.;. Such polymers are usually characterized on the basis of theiralkoxy or silica group content but it is often easier to measure thesilica (a complete hydrolysis of a sample) than the alkoxy groups.

These polymers can be prepared by well known methods such as thosedescribed in Chemistry and Technology of Silicones by W. Noll, page 648to 653. In order that the polymers produced shall be compatible withand/or shall react with the other ingredients employed in thecompositions of this invention, it is however necessary that they shouldstill possess the ability to dissolve in the usual hydrocarbon solventssuch as toluene, xylene and methylcyclohexane, in an amount of at least50 parts of polymer per 100 parts of solvent.

The organic derivatives of titanium, used in an amount of 0.2 to 6parts, preferably 0.3 to 5 parts, per 100 parts ofa,w-dihydroxydiorganopolysiloxane polymers, are, as already indicated,monomers of formula 4 (B), polymers resulting from the partialhydrolysis of alkyl titanates of formula Ti(OR) or chelates of formula(C) or (D).

Specific examples of alkyl radicals with one to 10 carbon atoms,represented by R in formulae (B) and (C), include, methyl, ethyl,propyl, isopropyl, butyl, isobutyl, hexyl, 2-ethyl-hexyl, octyl anddecyl radicals.

Specific examples of alkyl radicals with one to four carbon atoms andalkoxy radicals with one to three carbon atoms, represented by Q informula (C), include, methyl, ethyl, propyl, isopropyl and butyl,methoxy, ethoxy, propoxy and isopropoxy radicals.

Specific examples of alkyl radicals with one to five carbon atoms,represented by Q, in formulae (C) and (D), include, methyl, propyl,isopropyl, butyl and pentyl radicals.

By way of indication, as monomers of the formula (B), the followingcompounds may be mentioned: propyl titanate, isopropyl titanate, butyltitanate, 2-ethylhexyl titanate, octyl titanate, decyl titanate,beta-(methoxy)-ethyl titanate, beta-(ethoxy)-ethyl titanate,beta(propoxy)-ethyl titanate and that of the formula Ti[(OCl-l CH OCHThe products resulting from the partial hydrolysis of titanates offormula Ti(OR) for example, the alkyl titanates mentioned above with theexception of the last three are polymers which can possess a linearstructure consisting of a succession of units of the formula and/or amore complex structure, as indicated in The Organic Chemistry ofTitanium by R. Feld and P. L. Cowe, pages 25 to 31. Furthermore, thestructure of these polymers has a close relationship with the value ofthe molar ratio of the starting reagents, that is to say alkyltitanates/water, the nature of the radicals R" and the conditions forcarrying out the hydrolysis. In order to characterize thesepolytitanates, it is preferable, as for the polysilicates, to refer totheir titanium oxide content, measured by complete hydrolysis of asample.

They should be stable and soluble in the usual hydrocarbon solvents inan amount of at least 50 parts of polytitanates per parts of solvent.

The titanium chelates of formula (C) can be prepared by reacting alkyltitanates of formula Ti(OR) with beta-diketones, beta-keto-esters orsubstituted phenolic derivatives. By way of illustration, it is possibleto use, as beta-diketones, those corresponding to the followingformulae: CH CO-CH COCH CH (CH COCH COCH (Cl-l CH- CO-CH COCH CH (CHCOCH COCH CH Cl and as beta-keto-esters, those corresponding to thefollowing formulae: CH COCH COOCH and Cl-l COCH- COOC H and assubstituted phenolic derivatives, salicylaldehyde, methyl salicylate,ethyl salicylate and propyl salicylate.

These chelates can be produced by simply mixing the reagents, at therate of 1 to 2 mols of chelating agent per 1 mol of alkyl titanates, andremoving the alcohol, R"OH, if necessary. Details of the workingprocedures are given by R. Feld and P. L. Cowe, loc cit. on pages 58 to66.

In order to make it easier to bring them into contact with otheringredients, it is particularly advantageous to use chelates which areliquid or which have rather low melting points, such as thosecorresponding to the formulae below:

(CH CHzCHZ ):r

l HC m h i Conventional inorganic fillers can be used to improve themechanical properties of the elastomers produced by curing thecompositions of the invention, in an amount of at most 100 parts, andpreferably about parts, per parts of hydroxylic diorganopolysiloxanepolymers.

Suitable fillers which can be employed include: inorganic materials,such as pyrogenic silica, precipitated silica, diatomaceous silica,ground quartz, aluminium silicates, mixed aluminium and magnesiumsilicates, zirconium silicate, mica powder, calcium carbonate, glasspowder and glass fibres, titanium oxides of the pyrogenic oxide andrutile type, iron oxides, zinc oxide, aluminium oxide, zirconium oxide,magnesium oxide, graphite, conducting or non-conducting lamp blacks,asbestos and calcined clay; or organic materials, such asphthalocyanines, cork powder, sawdust, synthetic fibres and syntheticpolymers, such as polytetrafluoroethylene, polyethylene and polyvinylchloride.

They can, if desired, be surface-modified by treatment withorganosilicon compounds usually employed for this purpose, such asdiorganocyclopolysiloxanes, hexaorganodisiloxanes, hexamethyldisilazaneand diorganocyclopolysilazanes (see, for example French Pat. Nos.1,136,884, 1,136,885 and 1,236,505, and British Patent Specification No.1,024,234). These fillers thus modified contain, in the majority ofcases, 3 to 30% of their weight or organosilicon compounds.

Also, apart from these fillers, plasticisers and/or organosiliconstabilisers can be present, in the same proportions, that is to say atmost 100 parts, and preferably about 70 parts, per 100 parts ofhydroxylic diorganopolysiloxane polymers. Suitable such productsinclude:

a,w-bis-(triorganosiloxy)-diorganopolysiloxane polymers of viscosity atleast 10 cPo at 25C, consisting essentially of diorganosiloxy units andat most 1% of monoorganosiloxy units, the organic radicals bonded to thesilicon atoms being methyl, vinyl or phenyl radicals, at least 60% ofthese organic radicals being methyl radicals. The viscosity of thesepolymers can be as high as 30 or 40 millions of cPo at 25 C, and theythus comprise oils with a fluid to viscous appearance and soft to hardrubbers. They are prepared by the usual techniques, described moreprecisely in French Pat. Nos. 978,058, 1,025,150 and 1,108,764;

liquid, branched methylpolysiloxane polymers having 1.6 to 1.9 organicgroups per silicon atom, consisting of (CH SiO (Cl-l SiO and CH SiOunits and containing 0.3 to 6% of hydroxyl groups. They 7 can beobtained by hydrolysis of the corresponding chlorosilanes, as disclosedin, for example, French Pat. No. 1,408,662; and diorganopolysiloxaneoils blocked by hydroxyl and- /or lower alkoxy groups, of low viscosity,generally from 2 to 1,000 cPo at C, the organic radicals bonded to thesilicon atoms being, as above, methyl, vinyl or phenyl radicals, atleast 40% of these organic radicals being methyl radicals; methoxy,ethoxy, isopropoxy, propoxy, butoxy, isobutoxy and tertiary butoxygroups may be mentioned as chain-blocking lower alkoxy groups. They canbe prepared by the usual techniques described for example in French Pat.Nos. 938,292, 1,014,674, 1,116,196; 1,278,281 and 1,276,619.

These products generally play the role of plasticisers or stabilisersand sometimes of thixotropic agents or of agents which facilitate theextrusion of the compositions of the present invention. They can alsomodify certain physical properties of the elastomers formed, for exampleadhesion and hardness.

The organosilicon resins which characterise the compositions of theinvention are as already mentioned. polymers consisting of units of theformula R'(CH SiO and SiO used in an amount of 0.5 to 8 parts,preferably 0.8 to 7 parts, per 100 parts of hydroxylicdiorganopolysiloxane polymers. Alkyl radicals with one to three carbonatoms, represented by R' may be methyl, ethyl, isopropyl and propylradicals.

These resins can be prepared easily from triorganohalogenosilanes and/orhexaorganodisiloxanes and sodium silicates, as described in French Pat.No. 1,046,736, or from alkyl silicates and trimganohalogenosilanes, asdescribed in French Pat. No. 1,134,005. The reaction is generallycarried out in inert diluents and the resins thus prepared can be storedin these diluents or the latter replaced wholly or partially by otherdiluents which are also ineret. For example, toluene, xylene,cyclohexane, methylcyclohexane and These resins possess varying amountsof hydroxyl groups bonded to silicon atoms, generally representingapproximately 0.5 to 5% of their weight.

In order to prepare the compositions of the present invention, it isrecommended that a device be used which makes it possible simultaneouslyto mix the various ingredients intimately in the absence of moisture andto remove the volatile materials present (solvents and polymers of lowmolecular weight).

The ingredients can be incorporated in any order whatsoever, atatmospheric pressure or below, and at a temperature ranging from ambienttemperature to 200C, it is however advantageous, so as to prevent themixtures from thickening suddenly and, consequently, to avoid timelosses to render them fluid again, first to mix thea,m-dihydroxydiorganopolysiloxane polymers, the fillers, the stabilisersand/or plasticisers, where appropriate, and the organosilicon resinsunder a pressure of approximately 5 to mm Hg, at a temperaturepreferably above 80C. This process makes it possible to remove thevolatile substances and the water present and to form homogeneous,stable and anhydrous base compositions. Finally, the organosiliconcompounds of formula (A) and/or the products resulting from the partialhydrolysis of alkyl silicates as well as the organic derivatives oftitanium are added to these base compositions, preferably at atmosphericpressure and in a dry atmosphere, with vigorous stirring untilhomogeneity is chlorobenzene may be mentioned as suitable diluents.

achieved. Occasionally, in order to render the compositions thusprepared more fluid, it is recommended to heat them for at least 1 hourat a temperature above C, and preferably for 2 to 3 hours at about 150C.Moreover, inert diluents, for example, toluene, xylene, heptane, whitespirit, cyclohexane, methylcyclohexane trichloroethylene,tetrachloroethylene, ethyl acetate or butyl acetate, can be used tomanufacture dispersions containing any proportion whatsoever of thecompositions of the present invention.

The compositions, which may or may not have been diluted, are stable forat least 6 months, and generally for several years, when stored; theycure rapidly on simple exposure to the atmosphere or in the presence oftraces of water. The rubbery products obtained possess good physicalproperties.

The compositions can thus be used in a variety of applications, such asjointing masonry, caulking boat bridges, gluing numerous materials,coating woven or non-woven products based on inorganic, organic orsynthetic fibres, covering sheets made of plastics or cellulosicmaterial and coating electrical and electronic equipment. They can thusbe used, not only for coldvulcanised silicone elastomers, but also forthe protection of delicate electrical or electronic devices. They areparticularly suitable for this last application because neither they northe elastomers made from them corrode leads and other parts made ofcopper; moreover, they do not require the prior application of anadhesion undercoat to the metal in order to adhere effectively thereto;the same applies for numerous other metal substrates such as anodised ornon-anodised aluminium, brass, bronze, tin, steel and zinc.

The following Examples further illustrate this invention; the parts areexpressed by weight.

EXAMPLE I The following compounds are mixed at C for 3 hours, under apressure of 10 mm of mercury so as to remove the volatile materials:

100 parts 1 8 parts 3.9 parts.

3.9 parts of ethyl orthosilicate and 1.3 parts of butyl titanate areadded at atmospheric pressure, with stirring and in the presence of agentle stream of dry nitrogen, to the mixture thus formed, cooled toabout 50C. A composition E is obtained which has the appearance of ahomogeneous and sticky paste. A portion E of this composition E isspread, in the atmosphere, the relative humidity of which is 50%, on oneof the two faces (previously coated with a non-stick agent) of glassplates. The layer deposited, of thickness approximately 2 mm, isnon-sticky to the touch after 8 hours of exposure and after 24 hours ithas changed, due to crosslinking, into a rubbery film which can bedetached easily.

A second portion E is aged in an accelerated manner by heating in aclosed medium for 24 hours at 100C, before being spread and cured likethe portion E, on glass plates.

A third portion E is placed in leakproof aluminium tubes for 6 monthsand then, after being stored for this 9 period, it is spread on glassplates and cured in the manof the formation of a greenish coating, thethickness of ner indicated for the portion E which increases with time.

The following physical properties are then measured on the elastomerfilms originating from the portions E EXAMPLE u E and E these filmsbeing 1 week old: 5 The following ingredients are mixed at 170C for 2Shore hardness in accordance with ASTM Standard hours, under a pressureof mm of mercury for the Specification D 676-59 T, tensile strength inpurpose of removing the volatile materials: kg/cm and correspondingelongation in in accordance with AFNOR Standard SpecificationaMDihydmxydiorganopolysn0mm, oi] T.46,002, dumb-bell shapes H andmodulus at 10 scqs ty 35.000 cPo at c, 100% elongation, which representsthe force in conslstmg of dlmethyls'loxy and 5% of diphenylsiloxy unitsI00 parts kg/cm necessary to produce an elongation of Pyrogenic silicawith a large specific 100% of samples cut up into dumb-bell shapes H"sated hexamcthy" pans The results of these measurements are given inTable I. ylene Solution or a resin 15 consisting of (CH -,SiO

(CH Si9., and SiO units, these By way of comparison, a composition E isprepared which is similar to the composition E but does not contain theresin consisting of (CH SiO and SiO units. 2376i 32 Pam It is spread onglass plates and it is found that the layer deposited is still sticky tothe touch after 24 hours of exposure to the atmosphere; it is necessaryto wait for 7 parts of an polyslhcate contammg 40% of 5111,62 a further48 hours of exposure in order to lift off the W F P lsopropyl tltaqateare Introduced with film resulting therefrom vigorous stirring, atatmospheric pressure and under a Furthermore, the following constituentsare placed in gentle streamoof dry mtrogen this i C0016? a small glassbottle of capacity 30 s which can be to about 140 C, and the whole isthen mixed at this sealed by means of a Screwed in Stopper: temperaturefor 2 hours. A slightly sticky, homogene- 2 a of water ous composition Fis thus obtained.

a freshly cleaned strip of copper, only a small part of A poftlon F1 ofthe co,mposlt,on F Spread on glass which is immersed in the water, andplates in the manner indicated in Example I. The layer a small test tubekept open, Containing 2 g of the deposited is non-sticky to the touchafter 7 hours of excomposition Ev posure to the atmosphere and after 24hours it has The bottle is closed quickly and the appearance of thechanged into rubbery mm which is easily detached Strip of is exangnedaster 1 Week; no Change in i fio iii ef g oiiion F of the composition Fis aged by its ori ina co our is o serve 2 By v /ay of comparison,compositions of the prior art g g a closad meclljlum for houlrstat gg lwhich are stable when stored in the absence of mois- Ore sprea F a We ong ass p 3 e ayer ture and which cure from ambient temperature to yielddeposited is non-sticky after 6 hours of exposure to the elastomers aresubstituted for the composition E, it atmosphere? being understood thata new glass bottle eqiupped as l g s i propfnies ih t'f l p mafnnerindicated above is used for each of these compositions. m m Xamp e i one 1 ms Ongmatmg tom The compositions used are described in Example 14 off g F1 a T bl French Pat. No. 2,067,636, the crosslinking agents e S 0656 measurements are gwen a 6 being organoiminoxyalkoxysilanes; inExample 2 of TABLE ii Corresponding Modulus at Tensile strengthelongation I007: elongation Shore hardness in kg/cni in 7! in kg/cmPortion F, 37 48 390 9.5 Portion F- 40 47 380 10.5

French Pat. No. 1,432,799, the crosslinking agent being the disiloxaneof the formula: A third'portion F is placed in leakproof aluminium (CHCH=NO) (CH )Si-OSi(CH )(ON= tubes. After 8 months storage, theappearance of this CHCH and in Example 2 of French Pat. No. portion F issimilar to that of a freshly prepared coml,l98,749, the crosslinkingagent being methyltriposition F; moreover, when cured in the atmosphere,it acetoxysilane. It is found that with all these composiyields elasticfilms possessing physical properties, the tions, the strips of copperbecome tarnished as a result values of which are similar to those givenin Table ll.

EXAMPLE Ill The following ingredients are mixed at 155C. for 3 hours.under a pressure of mm of mercury for the purpose of removing thevolatile materials:

100 parts 2 parts 5 parts parts a r being in the numerical ratio0.35/0.15/1

5 parts 4.4 parts of a compound of the formula Si(OCH C- H OCH and 2parts of a butyl polytitanate containing 33% of titanium oxide areincorporated with stirring, at atmospheric pressure and under a gentlestream of dry nitrogen, into this mixture, cooled to about 60C 12 aremixed at a temperature of 150C for 3 hours and under a pressure of 10 mmof mercury. 2 parts ofa titanium chelate of the formula:

and 4 parts of an organosilicon compound chosen from amongst those ofthe formulae CH Si(OCH C H Si(OC1-1 CH %HSi(OCH Cl-1 OCH and Si- (OC Hare added, at atmospheric pressure and in the presence of a gentlestream of dry nitrogen, to the mixture thus formed, kept at atemperature of about 140C. The whole is then mixed for 2 hours at atemperature of 140C. Each composition obtained, which has the appearanceof an unctuous paste, is divided into two substantially equal portions;one of the portions is spread on glass plates in the manner indicated inExample 1. After a period of 24 hours, the rubbery films resultingtherefrom are detached from the plates and then left for 7 days in theatmosphere. After this period of time, their physical properties aremeasured. The

The composition thus formed is firm and thick and 25 values f d are as fll TABLE III Viscosity Physical properties of the oil TensileCorresponding in cPo at Organosilicon Shore strength elongation inCompositions 25C compound hardness in kglcm 5 28.000 CH Si(OCH,,) 27 22450 S 28.000 C H Si(OCH,1), 24 20 580 5:, 20.000 CH. ,=CHSi(OCH- C- 2924 500 2 a)n S 20.000 Si(OC H,,) 28 23 450 does not run when applied tovertical surfaces.

A portion thereof is deposited, in the manner indicated in Example 1, onglass plates; the layer spread is non-sticky after 4 hours of exposureto the atmosphere and after 18 hours it has changed into a rubbery filmwhich is detached easily from the plates.

After this film has been aged for 7 days, it possesses the followingmechanical properties: Shore hardness 20, tensile strength in kg/cm 17,corresponding elongation in 7: 470 and modulus at 100% elongation inkg/cm 3. The other portion is packaged in sealed aluminium tubes. After8 months storage, the appearance of the composition is similar to thatof a composition which has just been prepared; the elastomer filmsproduced therefrom also show physical properties which are quite normal,the values of which are similar to those given above.

EXAMPLES IV 4 different compositions S S S and S, are used, each ofwhich is prepared as described below.

100 parts 1 8 parts 4 parts are left exposed to the atmosphere for 7days. The adhesion to the metal plates of the elastomers thus formed isthen evaluated by rupture of the combinations due to shear, using atensometer. It is found that all the ruptures are cohesive, that is tosay that they take place within the body of the elastomers and not atthe plateelastomer interfaces.

EXAMPLE V The following compounds are mixed at 150C for 3 hours under apressure of 10 mm of mercury:

mm-Dihydroxydimethylpolysiloxane oil of viscosity 28.000 cPo at 25Cparts Pyrogenic silica with a large specific surface area. treated withhexamethyldisilazane 18 parts 60% toluene solution of a resin consistingof (CH,-,) SiO and SiO: units distributed 4 parts in the numerical ratio0.65/1

4 parts of n-propyl silicate, and 1.5 parts of a titanium chelate of theformula:

prepared in accordance with Example 2 of French Pat. No. 2,121,289, areadded, at atmospheric pressure and with stirring (the apparatus beingisolated from the atmosphere by passing a gentle stream of dry nitrogen)to the mixture, cooled to about 50C. An unctuous paste is obtained, aportion of which is spread in the atmosphere on glass plates in themanner indicated in Example 1. After the rubbery films resultingtherefrom have been left in the atmosphere for 7 days, they possess aShore hardness of 25, a tensile strength of 18 kg/cm and a correspondingelongation of 380%. The other portion of the composition is aged byheating in a closed medium for 24 hours at 100C and is then spread onglass plates as before; the films formed have physical properties, thevalues of which are of the same order as those given above.

We claim:

1. An organopolysiloxane composition which consists essentially of amixture of the following ingredients, by weight:

i. 100 parts of a a,w-dihydroxydiorganopolysiloxane polymer, ofviscosity at least about 600 cPo at 25C, consisting essentially ofdiorganosiloxy units, the organic radicals bonded to the silicon atomsbeing selected from alkyl radicals with one to three carbon atoms,halogenalkyl radicals with three or four carbon atoms, the vinylradical, aryl or halogenoaryl radicals with six to eight carbon atoms orcyanoalkyl radicals with three or four carbon atoms, with the provisothat at least 50% of these organic radicals are methyl radicals;

ii. 1 to parts of an organosilicon compound which is either:

a. a monomer of the formula (A): R,Si[(OCl-l CH- ),,OR],, in which Rrepresents a hydrogen radical with one to eight carbon atoms, Rrepresents an alkyl radical with one to four carbon atoms, and .r and aindependently represent zero or 1, or

b. a polymer resulting from the partial hydrolysis of at least onemonomer of formula Si(OR) in which R is as defined above;

iii. 0.2 to 6 parts of an organic derivative of titanium,

which is either:

a. a monomer of the formula (B): Ti[(OCl-l Cl-l OR"] in which Rrepresents an alkyl radical with one to 10 carbon atoms and b representszero, one or 2; such that when b is zero, the alkyl radical has three to10 carbon atoms and when I) is l or 2, the alkyl radical has one to fourcarbon atoms,

b. a polymer resulting from the partial hydrolysis of at least onemonomer of the formula Ti(OR") in which R represents an alkyl radicalwith three to 10 carbon atoms,

c. a titanium chelate of the formula (C):

in which Q represents an alkyl radical with one to four carbon atoms, aphenyl radical or an alkoxy radical with one to three carbon atoms; Rrepresents an alkyl 10 radical of three to 10 carbon atoms; y represents2 or 3;

R represents a hydrogen atom, a methyl radical or a chloromethylradical; Q represents an alkyl radical with one to five carbon atoms ora chloromethyl radical; or R and Q, together with the two carbon atomsl5 to which they are attached, together form a phenyl nucleus, in whichcase Q represents an alkoxy radical or a hydrogen atom, or

d. a titanium chelate of the formula (D):

in which R and R which may be identical or different, represent hydrogenatoms or methyl radicals; Q, Q and R are as defined above and nrepresents zero or 1;

iv. 0 to 100 parts of an optionally organosilicontreated inorganicfiller; v. 0 to 100 parts of plasticiser and/or organosilicon stabiliserand; vi. 0.5 to 8 parts of an organosilicon resin consisting of units ofthe formulae R"(CH SiO and SiO in which R' represents an alkyl radicalwith one to three carbon atoms or the vinyl radical and the ratio of thenumber of R(Cl-l Si- 0 units to the number of SiO units is from about0.4/1 to about 1.2/1.

2. A composition according to claim 1, in which the organosiliconcompound is selected from methyltrimethoxysilane,ethyltr'imethoxysilane, vinyl-tri-(B- methoxyethoxy)silane, ethylsilicate, propyl silicate, B-methoxyethyl silicate or ethyl polysilicatecontaining 40% of silica.

3. A composition according to claim 1, in which the organic derivativeof titanium is selected from isopropyl titanate, butyl titanate, butylpolytitanate containing 33% of titanium oxide, or a chelate of theformula:

4. A composition according to claim 1 in which component (ii) is presentin an amount from 2 to 12 parts.

5. A composition according to claim 1 in which component (iii) ispresent in an amount from 0.3 to 5 parts. 5

6. A composition according to claim 1 in which component (vi) is presentin an amount from 0.8 to 7 parts.

7. A process for preparing a composition as defined ture above C andthen to mix in components (ii) and (iii) at atmospheric pressure in adry atmosphere. l I l l

1. AN ORGANOPOLYSILOXANE COMPOSITION WHICH CONSISTS ESSENTIALLY OF AMIXTURE OF THE FOLLOWING INGREDIENTS, BY WEIGHT: I. 100 PARTS OF AA,W-DIHYDROXYDIORGANOPOLYXILOXANE POLYMER, OF VISCOSITY AT LEAST ABOUT600 CPO AT 25*C, CONSISTING ESSENTIALLY OF DIORGANOSILOXY UNITS, THEORGANIC RADICALS BONDED TO THE SILICON ATOMS BEING SELECTED FROM THALKYLRADICALS WITH ONE TO THREE CARBON ATOMS, HALOGENALKYL RADIALS WITH THREEOR FOUR CARBON ATOMS, THE VINYL RADICAL, ARYL OR HALOGENOARYL RADICALSWITH SIX TO EIGHT CARBON ATOMS OR CYCLOALKYL RADICALS WITH THREE OR FOURCARBON ATOMS, WITH THE PROVISO THAT AT LEAST 50% OF THESE ORGANICRADICALS RADICALS ARE METHYL RADICALS; II. 1 TO 15 PARTS OF ANORGANOSILICON COMPOUND WHICH IS EITHER; A. A MONOMER OF THE FORMULA (A):RXSI(OCH2CH2)AOR'')4-X, IN WHICH R REPRESENTS A HYDROGEN RADICAL WITHONE TO EIGHT CARBON ATOMS, R REPRESENTS AN ALKYL RADICAL WITH ONE TOFOUR CARBON ATOMS, AND X AND A INDEPENDENTLY REPRESENT ZERO OR 1, OR B.A POLYMER RESULTING FROM THE PARTIAL HYDROLYSIS OF AT LEAST ONE MONOMEROF FORMULA SI(OR'')4, IN WHICH R'' IS AS DEFINED ABOVE; III. 0.2 TO 6PARTS OF AN ORGANIC DERIVATIVE OF TITANIUM, WHICH IS EITHER: A. AMONOMER OF THE FORMULA (B9: TI((OCH2CH2)BOR")4, IN WHICH R" REPRESENTSAN ALKYL RADICAL WITH ONE TO 10 CARBON ATOMS AND B REPRESENTS ZERO, ONEOR 2; SUCH THA WHEN B IS ZERO, THE ALKYL RADICAL HAS THREE TO 10 CARBONATOMS AND WHEN B IS 1 OR 2, THE ALKYL RADICAL HAS ONE TO FOUR CARBONATOMS, B. A POLYMER RESULTING FROM THE PARTIAL HYDROLYSIS OF AT LEASTONE MONOMER OF THE FORMULA TI(OR")4, IN WHICH R" REPRESENTS AN ALKYLRADICAL WITH THREE TO 10 CARBON ATOMS, C. A TITANIUM CHELATE OF THEFORMULA (C);
 2. A composition according to claim 1, in which theorganosilicon compound is selected from methyltrimethoxysilane,ethyltrimethoxysilane, vinyl-tri-( Beta -methoxyethoxy)silane, ethylsilicate, propyl silicate, Beta -methoxyethyl silicate or ethylpolysilicate containing 40% of silica.
 3. A composition according toclaim 1, in which the organic derivative of titanium is selected fromisopropyl titanate, butyl titanate, butyl polytitanate containing 33% oftitanium oxide, or a chelate of the formula:
 4. A composition accordingto claim 1 in which component (ii) is present in an amount from 2 to 12parts.
 5. A composition according to claim 1 in which component (iii) ispresent in an amount from 0.3 to 5 parts.
 6. A composition according toclaim 1 in which component (vi) is present in an amount from 0.8 to 7parts.
 7. A process for preparing a composition as defined in claim 1which comprises mixing the specified ingredients in the absence ofmoisture.
 8. A process according to claim 7 which comprises mixingcomponents (i) and (vi), and (iv) and (v) if desired, under a pressureof 5 to 30 mm Hg at a temperature above 80*C and then to mix incomponents (ii) and (iii) at atmospheric preSsure in a dry atmosphere.